Node locations as persistent linked lists

Author: jg-rp

jsonpath_rfc9535/location.py

@@ -0,0 +1,33 @@
+"""JSONPath node locations as persistent linked lists."""
+
+from __future__ import annotations
+
+from typing import Iterator
+from typing import Optional
+from typing import Union
+
+
+class Location:
+    """JSONPath node location."""
+
+    __slots__ = ("value", "next")
+
+    def __init__(
+        self, value: Union[int, str, None], _next: Optional[Location] = None
+    ) -> None:
+        self.value = value
+        self.next = _next
+
+    def __iter__(self) -> Iterator[Union[int, str]]:
+        if self.value is not None:
+            yield self.value
+
+        _next = self.next
+        while _next is not None:
+            if _next.value is not None:
+                yield _next.value
+            _next = _next.next
+
+    def prepend(self, value: Union[int, str]) -> Location:
+        """Return a copy of this location with _value_ appended to the front."""
+        return Location(value, self)

jsonpath_rfc9535/node.py

@@ -5,10 +5,10 @@
 from typing import TYPE_CHECKING
 from typing import List
 from typing import Tuple
-from typing import Union
 
 if TYPE_CHECKING:
     from .environment import JSONValue
+    from .location import Location
 
 
 class JSONPathNode:
@@ -29,17 +29,20 @@ def __init__(
         self,
         *,
         value: object,
-        location: Tuple[Union[int, str], ...],
+        location: Location,
         root: JSONValue,
     ) -> None:
         self.value: object = value
-        self.location: Tuple[Union[int, str], ...] = location
+        self.location: Location = location
         self.root = root
 
     def path(self) -> str:
         """Return the normalized path to this node."""
         return "$" + "".join(
-            (f"['{p}']" if isinstance(p, str) else f"[{p}]" for p in self.location)
+            (
+                f"['{p}']" if isinstance(p, str) else f"[{p}]"
+                for p in reversed(list(self.location))
+            )
         )
 
     def __str__(self) -> str:

jsonpath_rfc9535/query.py

@@ -7,6 +7,7 @@
 from typing import Optional
 from typing import Tuple
 
+from .location import Location
 from .node import JSONPathNode
 from .node import JSONPathNodeList
 from .segments import JSONPathRecursiveDescentSegment
@@ -69,7 +70,7 @@ def finditer(
         nodes: Iterable[JSONPathNode] = [
             JSONPathNode(
                 value=value,
-                location=(),
+                location=Location(None),
                 root=value,
             )
         ]

jsonpath_rfc9535/segments.py

@@ -90,7 +90,7 @@ def _visit(self, node: JSONPathNode, depth: int = 1) -> Iterable[JSONPathNode]:
                 if isinstance(val, (dict, list)):
                     _node = JSONPathNode(
                         value=val,
-                        location=node.location + (name,),
+                        location=node.location.prepend(name),
                         root=node.root,
                     )
                     yield from self._visit(_node, depth + 1)
@@ -99,7 +99,7 @@ def _visit(self, node: JSONPathNode, depth: int = 1) -> Iterable[JSONPathNode]:
                 if isinstance(element, (dict, list)):
                     _node = JSONPathNode(
                         value=element,
-                        location=node.location + (i,),
+                        location=node.location.prepend(i),
                         root=node.root,
                     )
                     yield from self._visit(_node, depth + 1)
@@ -177,13 +177,13 @@ def _nondeterministic_children(node: JSONPathNode) -> Iterable[JSONPathNode]:
         for name, val in items:
             yield JSONPathNode(
                 value=val,
-                location=node.location + (name,),
+                location=node.location.prepend(name),
                 root=node.root,
             )
     elif isinstance(node.value, list):
         for i, element in enumerate(node.value):
             yield JSONPathNode(
                 value=element,
-                location=node.location + (i,),
+                location=node.location.prepend(i),
                 root=node.root,
             )

jsonpath_rfc9535/selectors.py

@@ -78,7 +78,7 @@ def resolve(self, node: JSONPathNode) -> Iterable[JSONPathNode]:
             with suppress(KeyError):
                 yield JSONPathNode(
                     value=node.value[self.name],
-                    location=node.location + (self.name,),
+                    location=node.location.prepend(self.name),
                     root=node.root,
                 )
 
@@ -127,7 +127,7 @@ def resolve(self, node: JSONPathNode) -> Iterable[JSONPathNode]:
             with suppress(IndexError):
                 _node = JSONPathNode(
                     value=node.value[self.index],
-                    location=node.location + (norm_index,),
+                    location=node.location.prepend(norm_index),
                     root=node.root,
                 )
                 yield _node
@@ -188,7 +188,7 @@ def resolve(self, node: JSONPathNode) -> Iterable[JSONPathNode]:
                 norm_index = self._normalized_index(node.value, idx)
                 _node = JSONPathNode(
                     value=element,
-                    location=node.location + (norm_index,),
+                    location=node.location.prepend(norm_index),
                     root=node.root,
                 )
                 yield _node
@@ -223,7 +223,7 @@ def resolve(self, node: JSONPathNode) -> Iterable[JSONPathNode]:
             for name, val in members:
                 _node = JSONPathNode(
                     value=val,
-                    location=node.location + (name,),
+                    location=node.location.prepend(name),
                     root=node.root,
                 )
                 yield _node
@@ -232,7 +232,7 @@ def resolve(self, node: JSONPathNode) -> Iterable[JSONPathNode]:
             for i, element in enumerate(node.value):
                 _node = JSONPathNode(
                     value=element,
-                    location=node.location + (i,),
+                    location=node.location.prepend(i),
                     root=node.root,
                 )
                 yield _node
@@ -286,7 +286,7 @@ def resolve(self, node: JSONPathNode) -> Iterable[JSONPathNode]:  # noqa: PLR091
                     if self.expression.evaluate(context):
                         yield JSONPathNode(
                             value=val,
-                            location=node.location + (name,),
+                            location=node.location.prepend(name),
                             root=node.root,
                         )
                 except JSONPathTypeError as err:
@@ -305,7 +305,7 @@ def resolve(self, node: JSONPathNode) -> Iterable[JSONPathNode]:  # noqa: PLR091
                     if self.expression.evaluate(context):
                         yield JSONPathNode(
                             value=element,
-                            location=node.location + (i,),
+                            location=node.location.prepend(i),
                             root=node.root,
                         )
                 except JSONPathTypeError as err: